右美托咪定对全麻下老年患者全膝关节置换术应激反应和拔管反应的影响

Effects of dexmedetomidine on stress reaction and extubation quality in elderly patients undergoing total knee arthroplasty with general anesthesia

目的探讨右美托咪定对全麻下老年患者全膝关节置换术（TKA）应激反应和拔管反应的影响。方法择期在全麻下行TKA的老年患者40例，ASAⅠ～Ⅲ级，年龄65-78岁，随机数字表法分为右美托咪定组（D组）和生理盐水对照组（C组）。D组麻醉诱导前泵注右美托咪定，负荷剂量0．5μg／kg，10min泵完，以0．4μg·kg^-1·h^-1维持；C组以同样方式泵注等量生理盐水。观察并记录给药前（T0）、给药后10min（T1）、气管插管时（T2）、切皮时（T3）、放置骨水泥（T4）、术毕（T5）、拔管后（T6）的MAP、HR。于T0、T2及T6时检测肾上腺素（E）、去甲肾上腺素（NE）的血浆浓度。记录拔管期间的呼吸恢复时间、拔管时间、苏醒时间、呛咳评分和躁动评分。结果与T0时比较，T1～T5时D组和T3、T4时C组MAP明显降低（P〈0．05）；T4、T5时D组HR明显减慢（P〈0．05）；T2、T6时C组血浆E、NE浓度明显升高（P〈0．05）。与C组比较，D组T1～T6时MAP明显降低（P〈0．05）；T2～T6时HR明显减慢（P〈0．05）；T2、T6时D组患者E、NE浓度明显降低（P〈0．05）。D组呛咳评分1分为13例（65％）、躁动评分为0～1分为17例（85％），分别多于C组的5例（25％）和12例（60％）（P〈0．05）。两组患者的呼吸恢复时间、苏醒时间及拔管时间比较差异无统计学意义。结论右美托咪定应用于全麻下TKA，可维持术中血压和心率的平稳，减少应激，预防气管插管、拔管时的不良反应，提高了拔管质量且不影响苏醒时间。

Objective To investigate effects of dexmedetomidine on stress reaction and extubation quality in elderly patients undergoing total knee arthroplasty （TKA） with general anesthesia. Methods Forty elderly patients with ASA Ⅰ- Ⅲ, aged 65-78 years old, undergoing TKA with general anesthesia, were randomly divided into Dex group （group D） and normal saline group （group C）. D exmedetomidine was given with 0. 5 μg/kg within 10 rain before anesthesia induction and followed with 0.4 μg·kg^-1·h^-1 in group D. The equal volume of normal saline was infused in group C. HR, MAP were observed at the time before dexmedetomidine infusion （T0）, 10 min after dexmedetomidine infusion （T1）, immediately after intubation （T2）, skin incision （T3）, implantation of bone cement immediately （T4）, surgery completion（T5 ） and after extubation （T6）. The plasma concentration of epinephrine and norepinephrine were detected at T0, T2 and T6. The intraoperative use of vasoactive drug was recorded. The respiratory recovery time, revival time, extubation time, bucking score and restlessness score were compared. Results Compared with To, MAP at T1-Ts in group D and at T3 ,T4 in group C were decreased significantly（P〈0.05）, HR at T4, Ts in group D were decreased（P〈0. 05）, the concentration of E and NE at T2 and T9 in group C were increased（P〈 0. 05）. Compared with group C,MAP at T1-T6 in group D were decreased, as well as HR at T2-T6 （P 〈0. 05）, the concentration of E and NE at T2 and T6 in group D were significantly deereased（P〈 0. 05）. 13（65%） cases scored 1 in bucking and 17（85~） scored 0-1in restless in group D, that were more than those in group C which were 5（25%） and 12（60~%） respectly（P〈0. 05）. There was no difference in respiratory time, revival time and extubation time between the two groups.